Wanted to post a follow-up to my original question, now that everything is in and working.
First, thanks for all the good feedback - helped me a lot in my planning and building.
Second, we ended up not directly connecting the TIGO-CCA to the SolArk - instead we used a double pole switch (see attached) to have the switch be the shutdown trigger, not the Tigo. In the end I like it this way, since it allows me to shut down the solar (if needed) without triggering the Sol-Ark shutting down.
View attachment 182936
The TS4-A-O's are working beautifully, doing a great job of keeping the voltage levels high, as the single tall shadow of the ONE tree moves across my panels as the day progresses.
a great combination of technology, Sol-Ark and Tigo. 10/10 would do it again.